A patent document 1, U.S. Pat. No. 6,779,499 (JP 2002-357105A) discloses a vane type variable valve timing apparatus. The variable valve timing apparatus may be referred to as a VVT. The VVT is installed in a drive train between a crankshaft of an internal combustion engine and a cam shaft which opens and closes a valve. The vane type VVT has a housing engaged with the crankshaft and a vane rotor engaged with the cam shaft. The housing and the vane rotor define an advance chamber and a retard chamber therebetween. The chambers are supplied with operating fluid, such as oil. The advance chamber is enlarged by being supplied with the oil when advancing valve timing. The retard chamber is enlarged by being supplied with the oil when retarding valve timing.
The vane type VVT may include a stopper member which locks the housing and the vane rotor at a predetermined relative position, such as a middle position or a most retard position. The stopper member may be located on the vane rotor. The stopper member locks the housing and the vane rotor by engaging itself into an engaging hole formed on the housing. For example, the stopper member may lock the housing and the vane rotor when the engine is in a starting, i.e. in a cranking stage or a slow rotational speed stage. The stopper member contributes to provide a secure and stable transmission of driving force from the crankshaft to the cam shaft, and to prevent noise caused by the housing and the vane rotor hit each other by relative rotational vibrations.